Circulating current minimization and current sharing control of parallel boost converters based on Droop Index
24 Oct 2013-pp 454-460
TL;DR: In this article, the authors investigated the relationship between current sharing difference and circulating current for two parallel connected dc-dc converters and proposed a new figure-of-merit called Droop Index, which is a function of normalized current sharing differences and losses in the output side of converters.
Abstract: This paper investigates the relationship between current sharing difference and circulating current for two parallel connected dc-dc converters. In the proposed algorithm a new figure-of-merit called Droop Index is introduced, which is a function of normalized current sharing difference and losses in the output side of the converters. This algorithm minimizes the circulating current and current sharing difference between the converters. Although there may exist a trade-off between current sharing difference and voltage regulation, the proposed droop index algorithm gives better performance and low voltage regulation. The detailed analysis and design procedure are explained for two dc-dc boost converters connected in parallel. The effectiveness of proposed method is verified using MATLAB simulation.
Citations
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TL;DR: In this paper, a figure of merit called droop index (DI) is introduced in order to improve the performance of dc microgrid, which is a function of normalized current sharing difference and losses in the output side of the converters.
Abstract: This paper addresses load current sharing and cir- culating current issues of parallel-connected dc-dc converters in low-voltage dc microgrid. Droop control is the popular technique for load current sharing in dc microgrid. The main drawbacks of the conventional droop method are poor current sharing and drop in dcgrid voltage due tothe droop action. Circulating current issue will also arise due to mismatch in the converters output voltages. In this work, a figure of merit called droop index (DI) is introduced in order to improve the performance of dc microgrid, which is a function of normalized current sharing difference and losses in the output side of the converters. This proposed adaptive droop con- trol method minimizes the circulating current and current sharing difference between the converters based on instantaneous virtual resistance Rdroop .U singRdroop shifting, the proposed method also eliminates the tradeoff between current sharing difference and voltage regulation. The detailed analysis and design procedure are explained for two dc-dc boost converters connected in paral- lel. The effectiveness of the proposed method is verified by detailed simulation and experimental studies.
343 citations
Cites background from "Circulating current minimization an..."
...The problems associated with voltage control are poor load sharing and circulating current between converters [12]....
[...]
TL;DR: Pro proportional droop index (PDI) algorithm with droop ( R droop ) shifting is introduced to improve the load sharing performance of the dc microgrid, which is a function of normalised current sharing difference and voltage deviation in the output side of the converters.
Abstract: This study discusses a droop-based proportional load sharing control of parallel connected dc-dc converters in photovoltaic (PV)-based low-voltage dc microgrid. Droop control is the popular scheme for power sharing in dc microgrid. In this study, proportional droop index (PDI) algorithm with droop (
R
droop
) shifting is introduced to improve the load sharing performance of the dc microgrid, which is a function of normalised current sharing difference and voltage deviation in the output side of the converters. This proposed control method calculates adaptive virtual resistance, R
droop
, and allows the converter to share the load current based on PV power available. By incorporating a new R
droop
shifting method with PDI, the proposed scheme eliminates the trade-off between current sharing and voltage regulation of the conventional method. The detailed analysis and design procedures are explained, and the effectiveness of the proposed method is verified by detailed simulation and experimental studies.
73 citations
TL;DR: The droop parameters of the proposed distributed control scheme are optimized with the help of the Particle Swarm Optimization technique for the aforementioned control objectives of the DC microgrid for unequal cable line resistances.
Abstract: The droop control approach is widely used in case of parallel operation of DC sources. The conventional droop control method is realized by linearly reducing the load voltage as the load current in...
17 citations
Cites background or methods from "Circulating current minimization an..."
...It is basically developed due to unbalance of cable line impedances, mismatch between droop gain, and output voltage of source converters [6]....
[...]
...In [6,12], the offset voltage is employed for compensating cable line voltage drop in order to compensate the limits of physical execution....
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01 Oct 2017
TL;DR: In this paper, the particle swarm optimization (PSO) technique was used to optimize the droop gain and voltage reference of a dc distributed control scheme to minimize the effect of the line impedances.
Abstract: In this paper, the droop gain and voltage reference are optimized to help of Particle Swarm Optimization (PSO) technique such that the effect of the line impedances is minimized which is well accommodated for marine applications. An optimization problem is formulated with necessary constraints for various loads. The performance of the droop controller with the optimal droop parameters of dc distributed control scheme is verified through a simulation implemented in the MATLAB/Simulink environment.
10 citations
06 Jul 2017
TL;DR: An improvisation is made in the conventional droop control strategy to obtain a better voltage regulation and improves the reliability of the system under various conditions.
Abstract: In a standalone DC microgrid connected with multiple renewable resources and storage elements, parallel dc-dc converters are more commonly used as interfacing unit between renewable energy sources and load. Current is shared between various power converters which are connected in parallel fashion to maintain a stable DC voltage in the grid. In order to ensure better load sharing in DC microgrid applications, droop control technique is more commonly used. But this control technique cannot ensure a decent level of voltage regulation. In order to address this problem, an improvisation is made in the conventional droop control strategy to obtain a better voltage regulation. This in turn improves the reliability of the system under various conditions. Proposed control technique is simulated and results are provided in this paper.
9 citations
References
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TL;DR: In this paper, a low-voltage bipolar-type dc microgrid is proposed to supply super high quality power with three-wire dc distribution line. But, the proposed system is not suitable for large-scale systems.
Abstract: Microgrid is one of the new conceptual power systems for smooth installation of many distributed generations (DGs). While most of the microgrids adopt ac distribution as well as conventional power systems, dc microgrids are proposed and researched for the good connection with dc output type sources such as photovoltaic (PV) system, fuel cell, and secondary battery. Moreover, if loads in the system are supplied with dc power, the conversion losses from sources to loads are reduced compared with ac microgrid. As one of the dc microgrids, we propose “low-voltage bipolar-type dc microgrid,” which can supply super high quality power with three-wire dc distribution line. In this paper, one system for a residential complex is presented as an instance of the dc microgrid. In this system, each house has a cogeneration system (CGS) such as gas engine and fuel cell. The output electric power is shared among the houses, and the total power can be controlled by changing the running number of CGSs. Super capacitors are chosen as main energy storage. To confirm the fundamental characteristics and system operations, we experimented with a laboratory scale system. The results showed that the proposed system could supply high-quality power under several conditions.
880 citations
"Circulating current minimization an..." refers background in this paper
...In this, dc microgrid plays a major role as it is highly efficient, reliable, controllable and economic [2], [3]....
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Book•
01 Jan 2008
TL;DR: In this paper, the authors present a classification of power supplies in DC-DC Converters, including voltage, current, voltage, energy, and power, and discuss the relationship among them.
Abstract: Preface. About the Author. List of Symbols. 1 Introduction. 1.1 Classification of Power Supplies. 1.2 Basic Functions of Voltage Regulators. 1.3 Power Relationships in DC-DC Converters. 1.4 DC Transfer Functions of DC-DC Converters. 1.5 Static Characteristics of DC Voltage Regulators. 1.6 Dynamic Characteristics of DC Voltage Regulators. 1.7 Linear Voltage Regulators. 1.8 Topologies of PWM DC-DC Converters 1.9 Relationships among Current, Voltage, Energy, and Power. 1.10 Electromagnetic Compatibility. 1.11 Summary. 1.12 References. 1.13 Review Questions. 1.14 Problems. 2 BuckPWMDC-DCConverter. 2.1 Introduction. 2.2 DC Analysis of PWM Buck Converter for CCM. 2.3 DC Analysis of PWM Buck Converter for DCM. 2.4 Buck Converter with Input Filter. 2.5 Buck Converter with Synchronous Rectifier. 2.6 Buck Converter with Positive Common Rail. 2.7 Tapped-Inductor Buck Converters. 2.8 Multiphase Buck Converter. 2.9 Summary. 2.10 References. 2.11 Review Questions. 2.12 Problems. 3 Boost PWM DC-DC Converter. 3.1 Introduction. 3.2 DC Analysis of PWM Boost Converter for CCM. 3.3 DC Analysis of PWM Boost Converter for DCM. 3.4 Bidirectional Buck and Boost Converters. 3.5 Tapped-Inductor Boost Converters. 3.6 Duality. 3.7 Power Factor Correction. 3.8 Summary. 3.9 References. 3.10 Review Questions. 3.11 Problems. 4 Buck-Boost PWM DC-DC Converter. 4.1 Introduction. 4.2 DC Analysis of PWM Buck-Boost Converter for CCM. 4.3 DC Analysis of PWM Buck-Boost Converter for DCM. 4.4 Bidirectional Buck-Boost Converter. 4.5 Synthesis of Buck-Boost Converter. 4.6 Synthesis of Boost-Buck (Cuk) Converter. 4.7 Noninverting Buck-Boost Converters. 4.8 Tapped-Inductor Buck-Boost Converters. 4.9 Summary. 4.10 References. 4.11 Review Questions. 4.12 Problems. 5 Flyback PWM DC-DC Converter. 5.1 Introduction. 5.2 Transformers. 5.3 DC Analysis of PWM Flyback Converter for CCM. 5.4 DC Analysis of PWM Flyback Converter for DCM. 5.5 Multiple-Output Flyback Converter. 5.6 Bidirectional Flyback Converter. 5.7 Ringing in Flyback Converter. 5.8 Flyback Converter with Active Clamping. 5.9 Two-Transistor Flyback Converter. 5.10 Summary. 5.11 References. 5.12 Review Questions. 5.13 Problems. 6 Forward PWM DC-DC Converter. 6.1 Introduction. 6.2 DC Analysis of PWM Forward Converter for CCM. 6.3 DC Analysis of PWM Forward Converter for DCM. 6.4 Multiple-Output Forward Converter. 6.5 Forward Converter with Synchronous Rectifier. 6.6 Forward Converters with Active Clamping. 6.7 Two-Switch Forward Converter. 6.8 Summary. 6.9 References. 6.10 Review Questions. 6.11 Problems. 7 Half-Bridge PWM DC-DC Converter. 7.1 Introduction. 7.2 DC Analysis of PWM Half-Bridge Converter for CCM. 7.3 DC Analysis of PWM Half-Bridge Converter for DCM. 7.4 Summary. 7.5 References. 7.6 Review Questions. 7.7 Problems. 8 Full-Bridge PWM DC-DC Converter. 8.1 Introduction. 8.2 DC Analysis of PWM Full-Bridge Converter for CCM. 8.3 DC Analysis of PWM Full-Bridge Converter for DCM. 8.4 Phase-Controlled Full-Bridge Converter. 8.5 Summary. 8.6 References. 8.7 Review Questions. 8.8 Problems. 9 Push-Pull PWM DC-DC Converter. 9.1 Introduction. 9.2 DC Analysis of PWM Push-Pull Converter for CCM. 9.3 DC Analysis of PWM Push-Pull Converter for DCM. 9.4 Comparison of PWM DC-DC Converters. 9.5 Summary. 9.6 References. 9.7 Review Questions. 9.8 Problems. 10 Small-Signal Models of PWM Converters for CCM and DCM. 10.1 Introduction. 10.2 Assumptions. 10.3 Averaged Model of Ideal Switching Network for CCM. 10.4 Averaged Values of Switched Resistances. 10.5 Model Reduction. 10.6 Large-Signal Averaged Model for CCM. 10.7 DC and Small-Signal Circuit Linear Models of Switching Network for CCM. 10.8 Family of PWM Converter Models for CCM. 10.9 PWM Small-Signal Switch Model for CCM. 10.10 Modeling of the Ideal Switching Network for DCM. 10.11 Averaged Parasitic Resistances for DCM. 10.12 Small-Signal Models of PWM Converters for DCM. 10.13 Summary. 10.14 References. 10.15 Review Questions. 10.16 Problems. 11 Open-Loop Small-Signal Characteristics of Boost Converter for CCM. 11.1 Introduction. 11.2 DC Characteristics. 11.3 Open-Loop Control-to-Output Transfer Function. 11.4 Delay in Open-Loop Control-to-Output Transfer Function. 11.5 Open-Loop Audio Susceptibility. 11.6 Open-Loop Input Impedance. 11.7 Open-Loop Output Impedance. 11.8 Open-Loop Step Responses. 11.9 Summary. 11.10 References. 11.11 Review Questions. 11.12 Problems. 12 Voltage-Mode Control of Boost Converter. 12.1 Introduction. 12.2 Circuit of Boost Converter with Voltage-Mode Control. 12.3 Pulse-Width Modulator. 12.4 Transfer Function of Modulator, Boost Converter Power Stage, and Feedback Network. 12.5 Error Amplifier. 12.6 Integral-Single-Lead Controller. 12.7 Integral-Double-Lead Controller. 12.8 Loop Gain. 12.9 Closed-Loop Control-to-Output Voltage Transfer Function. 12.10 Closed-Loop Audio Susceptibility. 12.11 Closed-Loop Input Impedance. 12.12 Closed-Loop Output Impedance. 12.13 Closed-Loop Step Responses. 12.14 Closed-Loop DC Transfer Functions. 12.15 Summary. 12.16 References. 12.17 Review Questions. 12.18 Problems. 13 Current-Mode Control. 13.1 Introduction. 13.2 Principle of Operation of PWM Converters with Peak-Current-Mode Control. 13.3 Relationship between Duty Cycle and Inductor-Current Slopes. 13.4 Instability of Closed-Current Loop. 13.5 Slope Compensation. 13.6 Sample-and-Hold Effect on Current Loop. 13.7 Current Loop in s -Domain. 13.8 Voltage Loop of PWM Converters with Current-Mode Control. 13.9 Feedforward Gains in PWM Converters with Current-Mode Control without Slope Compensation. 13.10 Feedforward Gains in PWM Converters with Current-Mode Control and Slope Compensation. 13.11 Closed-Loop Transfer Functions with Feedforward Gains. 13.12 Slope Compensation by Adding a Ramp to Inductor Current. 13.13 Relationships for Constant-Frequency Current-Mode On-Time Control. 13.14 Summary. 13.15 References. 13.16 Review Questions. 13.17 Problems. 13.18 Appendix: Sample-and-Hold Modeling. 14 Current-Mode Control of Boost Converter. 14.1 Introduction. 14.2 Open-Loop Small-Signal Transfer Functions. 14.3 Open-Loop Step Responses of Inductor Current. 14.5 Closed-Voltage-Loop Transfer Functions. 14.6 Closed-Loop Step Responses. 14.7 Closed-Loop DC Transfer Functions. 14.8 Summary. 14.9 References. 14.10 Review Questions. 14.11 Problems. 15 Silicon and Silicon Carbide Power Diodes. 15.1 Introduction. 15.2 Electronic Power Switches. 15.3 Intrinsic Semiconductors. 15.4 Extrinsic Semiconductors. 15.5 Silicon and Silicon Carbide. 15.6 Physical Structure of Junction Diodes. 15.7 Static I - V Diode Characteristic. 15.8 Breakdown Voltage of Junction Diodes. 15.9 Capacitances of Junction Diodes. 15.10 Reverse Recovery of pn Junction Diodes. 15.11 Schottky Diodes. 15.12 SPICE Model of Diodes. 15.13 Summary. 15.14 References. 15.15 Review Questions. 15.16 Problems. 16 Silicon and Silicon Carbide Power MOSFETs. 16.1 Introduction. 16.2 Physical Structure of Power MOSFETs. 16.3 Principle of Operation of Power MOSFETs. 16.4 Derivation of Power MOSFET Characteristics. 16.5 Power MOSFET Characteristics. 16.6 Mobility of Charge Carriers. 16.7 Short-Channel Effects. 16.8 Aspect Ratio of Power MOSFETs. 16.9 Breakdown Voltage of Power MOSFETs. 16.10 Gate Oxide Breakdown Voltageof Power MOSFETs. 16.11 Resistance of Drift Region. 16.12 Figures-of-Merit. 16.13 On-Resistance of Power MOSFETs. 16.14 Capacitances of Power MOSFETs. 16.15 Switching Waveforms. 16.16 SPICE Model of Power MOSFETs. 16.17 Insulated Gate Bipolar Transistors. 16.18 Heat Sinks. 16.19 Summary. 16.20 References. 16.21 Review Questions. 16.22 Problems. 17 Soft-Switching DC-DC Converters. 17.1 Introduction. 17.2 Zero-Voltage-Switching DC-DC Converters. 17.3 Buck ZVS Quasi-Resonant DC-DC Converter. 17.4 Boost ZVS Quasi-Resonant DC-DC Converter. 17.5 Zero-Current-Switching DC-DC Converters. 17.6 Boost ZCS Quasi-Resonant DC-DC Converter. 17.7 Multiresonant Converters. 17.8 Summary. 17.9 References. 17.10 Review Questions. 17.11 Problems. Appendix A Introduction to SPICE. Appendix B Introduction to MATLAB. Answers to Problems. Index.
734 citations
"Circulating current minimization an..." refers methods in this paper
...This can be applied for parallel dc-dc boost converter [14] as shown in Fig....
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01 Aug 2001
TL;DR: The technical status, cost, and applications of major renewable energy technologies and implications for increased adoption of renewables will be reviewed.
Abstract: Energy is essential to our society to ensure our quality of life and to underpin all other elements of our economy. Renewable energy technologies offer the promise of clean, abundant energy gathered from self-renewing resources such as the sun, wind, earth, and plants. Virtually all regions of the United States and the world have renewable resources of one type or another. Renewable resources currently account for about 10% of the energy consumed in the United States, most of this is from hydropower and traditional biomass sources. Wind, solar biomass, and geothermal technologies are cost-effective today in an increasing number of markets, and are making important steps to broader commercialization. Each of the renewable energy technologies is in a different stage of research, development, and commercialization, and all have differences in current and future expected costs, current industrial base, resource availability, and potential impact on greenhouse gas emissions. The technical status, cost, and applications of major renewable energy technologies and implications for increased adoption of renewables will be reviewed.
589 citations
"Circulating current minimization an..." refers background in this paper
...(ii) Non conventional sources of energy are renewable [1]....
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01 Jul 1999
TL;DR: This paper classifies and examines these paralleling schemes, focusing on the active current-sharing approaches, and finds that some new paralleled schemes can be achieved.
Abstract: There is a fairly large number of methods for paralleling power converters. This paper classifies and examines these paralleling schemes, focusing on the active current-sharing approaches. Based on this classification, some new paralleling schemes can be achieved. Emphasis is placed on discussion and assessment of merits and limitations of these schemes. Finally, the prominent features of the dominant paralleling schemes are verified by simulation of a two-paralleled buck converter system.
424 citations
"Circulating current minimization an..." refers background in this paper
...Operation and control of parallel connected converters [4]- [6] are important and some advantages are (i) expandability of output power (ii) reliability (iii) efficiency (iv) ease of maintenance....
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16 Sep 2008
392 citations